As a broadly trained life scientist, my concern about climate change isn’t the health of the planet. The rocks will be just fine! What worries me is a whole spectrum of “wicked” challenges, from sustaining food production, to providing clean water, to maintaining wildlife diversity and the green environments that ensure the survival of complex life on Earth.

What’s more, as a disease and death researcher, I think of climate change as equivalent to lead poisoning: slow, cumulative, progressive and initially silent but, if not treated in time, causing irreversible, catastrophic damage.

We need legislators who can think and act for the long term. This issue is simply too big for individuals or volunteer groups. Unless politicians are prepared to put a substantial price on greenhouse emissions, it’s difficult to see how a capitalist economic system can move us forward. Clean coal? The US 45Q tax reform, which offers credits for carbon capture and storage projects, suggests we would need a carbon price of at least US$50 a tonne to make this technology economically feasible.

Australia’s governments at every level could be acting now to promote the planting of vegetation, including less readily combustible tree species. We could be embracing, and funding, energy efficiency while constructing all new buildings – especially hospitals and large apartment complexes – in ways that protect their inhabitants. A realistic carbon tax could pay for some of that, while also stimulating jobs and growth and providing investment certainty.

Some moves are already being made in the right direction. The Gorgon gas project is planning to extend its strategy to inject carbon dioxide into the ground rather than releasing it to the atmosphere. CSIRO’s new hydrogen economy roadmap shows how (with the endorsement of Chief Scientist Alan Finkel) we can develop gas exports based on hydrogen rather than natural gas, to supply emerging markets in countries such as Japan.

A more familiar export product is wood. Planting and harvesting trees mimics nature’s mechanism for storing carbon. Perhaps it’s time for CSIRO and the universities to reinvest in developing wood technologies that displace concrete for at least some forms of construction. Modular wooden houses could also easily be moved away from low-lying areas hit by river flooding and sea level rise.

My wife Penny and I recently joined a small organised tour that took us more than 5,000km around Western Australia. That made us very aware of competing realities. On one hand, we have the human constructs of community, politics and economy. On the other is the reality of nature, imposed by the laws of physics and the fact that all life systems have evolved to live within defined environmental “envelopes”.

Apart from the glorious WA wildflowers and extensive wheat fields, the prominence of mining was very clear. Metals are essential for just about any renewable energy strategy, although the massive amounts of diesel burned in the extraction process are clearly an issue. Could that transition to carbon-neutral biodiesel?

If ethanol is bad for internal combustion engines, perhaps we should revisit external combustion? In WA, we went to the HMAS Sydney memorial in Geraldton. Like all big ships of her time, the Sydney was powered by steam turbines. Turbine power generation could be part of a mix driving electric/wind ships of the future.

Our WA trip also made us very conscious of the complex ecosystems that, in the end analysis, sustain all life. Plants use chemical signals (plant pheromones) to “talk” among themselves, to other species, and to the insects they attract for
pollination. Some plants rely for reproduction on a single insect species. If the
insects die, they die. We’re currently in the sixth mass extinction – this one caused by humans. As temperatures ramp up, rainfall patterns change, and firestorms grow stronger and more frequent, the effects will be terminal for many species.

With much of our land unsuited to agriculture, Australia is the biggest solar
collector on Earth. Visiting WA also made us very aware of the enormous, untapped
wind potential on the west coast. Apart from battery storage, making hydrogen from seawater offers an obvious strategy for dealing with both the remoteness of generation sites and the variability of supply from renewables, while also returning oxygen to the atmosphere. We could be the clean energy giants!

None of this will happen without the help of major corporations that have the wealth and power to influence governments, along with the globalised structure that facilitates the development and implementation of solutions. What’s very encouraging is that many of the multinationals are now moving forward to develop strategies for supplying global energy needs while minimising greenhouse gas emissions. There’s no way they want to be the “tobacco villains” of the 21st century!

This is an adapted version of a speech given in Melbourne on October 24 at the international ghgt-14 meeting.

The climate is changing before our eyes. News articles about imminent species extinctions have become the norm. Images of oceans full of plastic are littering social media. These issues are made even more daunting by the fact that they are literally global in scale.

In the face of these global environmental crises it can be hard to know where to start to help change the state of our planet. But in a paper published in the journal Sustainable Earth, we set out how to translate many of our global environmental issues into action at a more manageable level.

Our approach aims to chop global problems into digestible chunks that you – as an individual, a chief executive, a city councillor, or a national committee member – can tackle.

We call it “planetary accounting”, because it is about creating a series of environmental “budgets” that will stop us overshooting the planet’s natural boundaries. From that, we can then calculate everyone’s fair share, and hopefully in the process make it easier to visualise which individual, corporate or community actions will have a real environmental impact.

The planetary boundaries, developed in 2009, are a set of non-negotiable global limits for factors such as temperature, water use, species extinctions and other environmental variables. These aim to quantify how far we can push the planet before threatening our very survival.

The nine planetary boundaries are listed below; exceeding any of these limits puts us at risk of irreversible global damage. We are currently exceeding four, so it’s fair to say the situation is urgent.

Despite providing important information about the health of our planet, the planetary boundaries fail to answer one very important question: what can we do about it?

The problem with the planetary boundaries is that they are limits for the environment, not for people. They cannot be easily related to human activities, nor do they make sense at smaller scales.

A national government would be hard-pressed to determine what a fair share of the world’s species extinctions might be. A commuter deciding whether to take the bus or drive to work doesn’t really know how her decision will affect the amount of carbon dioxide in the atmosphere. The planetary boundaries measure outcomes; they do not prescribe actions.

The ecological footprint – which estimates how many Earths would be required for a given level of human activity – has long been used as a tool for environmental policy and action. But many experts think this measure is too simplistic. How can a single statistic possibly capture the range and complexity of human impacts on our planet?

Planetary accounting

This is where planetary accounting comes in. It offers a new approach to understanding the global impacts of any scale of human activity. It takes the “safe operating space” defined by the planetary boundaries, and then uses these limits to derive a set of quotas that we can act on.

Using this approach, we have drawn up a set of ten global budgets for environmental factors, including carbon dioxide emissions, release of nitrogen to the environment, water consumption, reforestation, and so on.

These budgets can then be divided among the world’s population in easily quantifiable units. That way, nations, cities, businesses and even individuals can begin to understand what their fair share actually looks like.

If the planetary boundaries are a health check for planet Earth, then you can think of these quotas as the prescription for a healthy global environment.

The Planetary Quotas are global budgets for environmental pressures that can be divided and managed at different levels and areas of society.Peter Newman/Kate Meyer, Author provided

To extend the health analogy, it’s rather like having a general checkup with a doctor, who might measure a range of variables such as your blood pressure, heart rate, weight and liver function. If any of these are outside the healthy range, the doctor might recommend a healthier diet, more exercise, or avoiding smoking or drinking too much.

Similarly, if we find we are exceeding our environmental fair share – say, by taking too much carbon-intensive transport, or eating too much nitrogen-intensive food – then we can begin to take action.

The planetary quotas.Peter Newman/Kate Meyer, Author provided

Planetary accounting is designed to work at a range of scales. We could use it to inform anything from individual actions, to city planning targets, to corporate sustainability goals, to global environmental negotiations.

It could even be “gamified”, perhaps in the form of apps that let players compete with one another to live within their share of global environmental budgets. Or it could be used to draw up “planetary labels” similar to the nutritional information labels that help keep food companies honest and the public informed.

Planetary Facts labels could be used to disclose the critical environmental impacts of goods and services.Peter Newman/Kate Meyer, Author provided

Planetary accounting won’t solve all the complex problems our planet faces. But it could make it easier to answer that all-important question: “What can I do to help?”

The dingo is Australia’s largest land-based predator, occurring across most of the mainland and on many nearshore islands.

Our new research, published in the journal Mammal Review, reveals the breadth and diversity of dingo diets across the continent.

We compiled and analysed 73 sets of data, containing details of more than 32,000 dingo droppings or stomach contents, to document the range of different species that dingoes eat, and how their diets vary between different environments.

A wide-ranging diet

We found that dingoes eat at least 229 vertebrate species. This includes 62 small mammals (less than 500 grams in mass), 79 medium-sized and larger mammals, 10 species of hoofed mammals, 50 birds and 26 reptiles. Dingoes also eat insects, crustaceans, centipedes, fish and frogs.

The true number of species is likely to be much higher because dingo diets have been poorly studied in many parts of Australia, such as Cape York Peninsula.

Large (at least 7kg) and medium-sized (0.5-6.9kg) mammals were the most common components of dingo diets, followed by small mammals, rabbits, arthropods, reptiles, birds and hoofed animals.

Average occurrence of eight food types in the diet of dingoes. Values represent the percentage of droppings/stomachs that contained each food type.

A range of introduced pest species also feature in dingo diets, including deer, goats, rabbits, hares, black rats, house mice, foxes and cats. In recent decades, the occurrence of sambar deer in dingo diets has increased as this invasive species has expanded its range.

Dingoes also eat sheep and cattle, although dietary samples are unable to distinguish between predation and scavenging, and hence tell us little about dingo impacts on livestock production. Dietary samples also do not reveal instances of dingoes killing livestock without eating them.

Regional variation

We found that what dingoes eat depends on where they live. For instance, in arid central Australia, birds, reptiles, rabbits, small mammals and insects form major parts of dingo diets. In contrast, these food groups are less important in temperate and subtropical eastern Australia, where medium-sized and large mammals such as kangaroos, bandicoots and possums are more important.

Frequency of different food groups in dingoes’ diet. Each circle represents a study and is scaled proportionally with dietary occurrence; larger circles represent a higher frequency of that food type. Top row: arthropods and small mammals (less than 500g); middle row: reptiles and medium-sized mammals (0.5-6.9kg); bottom row: rabbits and large mammals (at least 7kg).

The higher occurrence of medium-sized mammals in dingo diets in eastern Australia may be due to the lower extinction rates of native mammals there. In contrast, central Australia is a global mammal extinction hotspot, which probably accounts for the low occurrence of medium-sized mammals in dingo diets in arid and semi-arid areas.

Nonetheless, one medium-sized mammal was a major food item for dingoes in arid areas: the European rabbit. In some areas, more than 50% of dingo droppings or stomachs contained the remains of this invasive species. It is possible that native medium-sized mammals previously constituted a major part of dingo diets in arid Australia, but have since been replaced by rabbits.

Local prey availability plays a major role in determining what dingoes eat. For instance, in the Tanami Desert, reptiles were most common in dingo diets during warmer months when they are most active. However, very few studies have collected data on prey availability, partly because of the sheer number of different animals that dingoes eat.

Threatened species

This tally is higher than the number of threatened species in feral cat diets (based on a previous study that used similar methods), even though cats eat almost twice as many different species overall as dingoes (400 and 229, respectively).

But now a combination of small population sizes of some threatened species and exacerbating factors such as habitat loss, foxes and cats means some threatened species could be vulnerable to even low levels of dingo predation. Predation by dingoes should therefore be a key consideration when attempting to conserve or restore threatened species.

Dietary studies are one way we can understand how dingoes interact with other species. Our study also highlights that we still have much to learn about our native top predator. In many parts of Australia, the favourite foods of dingoes are still a mystery.